import java.util.Scanner;

/*
    @author:sa
    @date:2024/11/7 14:12
*/
public class ifDemo02 {
    public static void main(String[] args) {
        System.out.println("输入月份");
        Scanner scanner = new Scanner(System.in);
        String mon1 = scanner.nextLine();
        int m1 = Integer.parseInt(mon1);
        if (m1==1|m1==3|m1==5|m1==7|m1==8|m1==10|m1==12){
            System.out.println("31天");
        }
        if (m1==4|m1==6|m1==9|m1==11){
            System.out.println("30天");
        }
        if (m1==2){
            System.out.println("28天");
        }
    }
}